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Read an annotation-dict entry by key

Source: R/annot_probes.R
pdf_annot_dict_value.Rd

Parallel to pdf_attachment_dict_value() but for annotations. Returns the typed value of a key in the annotation's dictionary — useful for ad-hoc access to keys pdf_annotations() doesn't surface (e.g. /M modification date, /NM unique name, /CA overall opacity, /RC rich-text contents).

Usage

pdf_annot_dict_value(annot, key)

Arguments

annot

A pdfium_annot handle (e.g. one element of pdf_annotations(page)).

key

The annotation-dict key as a single non-empty character string (ASCII PDF name, e.g. "M", "NM", "CA").

Value

A list with four fields:

  • has_key (logical) — TRUE when the annotation dict contains key.

  • value_type (integer) — PDFium's FPDF_OBJECT_* enum value (0=unknown, 1=boolean, 2=number, 3=string, 4=name, ...); NA when the key is absent.

  • value_string (character) — populated when the value is a PDF string or name; NA_character_ otherwise.

  • value_number (numeric) — populated when the value is a PDF number; NA_real_ otherwise.

Details

Wraps FPDFAnnot_HasKey, FPDFAnnot_GetValueType, FPDFAnnot_GetStringValue, and FPDFAnnot_GetNumberValue. Only string-, name-, and number-typed values come back; other value types (dict / array / stream / reference) report value_type accordingly but leave the typed accessors as NA.

See also

pdf_annotations() for the structured per-annotation readout, pdf_annot_appearance() for the /AP appearance stream.